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enigma.cc
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enigma.cc
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#include <strings.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <ctype.h>
#include <sys/stat.h>
#include <fcntl.h>
/* uwwwrrrggg = 3*8*7*6*26*26*26*26*26*26 = 311 387 102 208 */
static const char * reflector_string[] =
{
"EJMZALYXVBWFCRQUONTSPIKHGD", // A
"YRUHQSLDPXNGOKMIEBFZCWVJAT", // B
"FVPJIAOYEDRZXWGCTKUQSBNMHL", // C
"MOWJYPUXNDSRAIBFVLKZGQCHET", // Norway
"ENKQAUYWJICOPBLMDXZVFTHRGS", // UKW-b M4 thin
"RDOBJNTKVEHMLFCWZAXGYIPSUQ" // UKW-c M4 thin
};
static const char * rotor_string[] =
{
"EKMFLGDQVZNTOWYHXUSPAIBRCJ", // i
"AJDKSIRUXBLHWTMCQGZNPYFVOE", // ii
"BDFHJLCPRTXVZNYEIWGAKMUSQO", // iii
"ESOVPZJAYQUIRHXLNFTGKDCMWB", // iv
"VZBRGITYUPSDNHLXAWMJQOFECK", // v
"JPGVOUMFYQBENHZRDKASXLICTW", // vi
"NZJHGRCXMYSWBOUFAIVLPEKQDT", // vii
"FKQHTLXOCBJSPDZRAMEWNIUYGV", // viii
"WTOKASUYVRBXJHQCPZEFMDINLG", // Norway i
"GJLPUBSWEMCTQVHXAOFZDRKYNI", // Norway ii
"JWFMHNBPUSDYTIXVZGRQLAOEKC", // Norway iii
"FGZJMVXEPBWSHQTLIUDYKCNRAO", // Norway iv
"HEJXQOTZBVFDASCILWPGYNMURK", // Norway v
"LEYJVCNIXWPBQMDRTAKZGFUHOS", // Beta
"FSOKANUERHMBTIYCWLQPZXVGJD" // Gamma
};
static const char * notch_string[] =
{
"Q",
"E",
"V",
"J",
"Z",
"MZ",
"MZ",
"MZ",
"Q",
"E",
"V",
"J",
"Z",
"",
""
};
static const int maxlen = 10240;
static const int asize = 26;
static const int wheels = 3;
static const int reflector_count = sizeof(reflector_string) / sizeof(char *);
static const int rotor_count = sizeof(rotor_string) / sizeof(char *);
static char * opt_ukw;
static char * opt_walzen;
static char * opt_ringstellung;
static char * opt_grundstellung;
static char * opt_steckerbrett;
static char * opt_logfilename;
static char * opt_plaintext; /* plaintext to compare to */
static char * opt_language; /* german (default), english, danish, french ... */
static int opt_norenigma; /* use the 5 Norenigma (Norway Enigma) wheels */
static int opt_maxwheel;
static int opt_scoring;
static int opt_threads;
static int opt_hillclimb;
static char ciphertext[maxlen+1];
static char plaintext[maxlen+1];
static char altplaintext[maxlen+1];
static int textlength;
static unsigned char rotor_fwd[rotor_count][asize];
static unsigned char rotor_rev[rotor_count][asize];
static unsigned char notch[rotor_count][asize];
static unsigned char reflector[reflector_count][asize];
static unsigned char steckerbrett[asize];
static int ukw;
static int walzenlage[wheels];
static unsigned char grundstellung[wheels];
static unsigned char ringstellung[wheels];
static unsigned char num_ciphertext[maxlen];
static unsigned char num_plaintext[maxlen];
static unsigned char subst_array[asize][asize][asize][asize];
static unsigned char mapping[maxlen][26];
static double monograms[26];
static double bigrams[26][26];
static double trigrams[26][26][26];
static double quadgrams[26][26][26][26];
void fatal(const char * message)
{
fprintf(stderr, "\nFatal error: %s\n", message);
exit(1);
}
inline int char2num(char x)
{
return x - 65;
}
inline char num2char(int x)
{
return 65 + x;
}
void monograms_read()
{
for(int i=0; i<26; i++)
monograms[i] = 1.0;
double total = 26;
FILE * f;
char filename[100];
strcpy(filename, opt_language);
strcat(filename, "_monograms.txt");
f = fopen(filename, "r");
if (!f)
{
fprintf(stderr, "Fatal error: Unable to open the language statistics file %s\n",
filename);
exit(1);
}
while(1)
{
char a;
int count;
int ret = fscanf(f, "%c %d\n", & a, & count);
if (ret > 0)
{
if ((a >= 'A') && (a <= 'Z'))
{
monograms[char2num(a)] = count + 1.0;
total += count;
}
}
else
break;
}
for(int i=0; i<26; i++)
monograms[i] = log10(monograms[i]);
fclose(f);
}
void bigrams_read()
{
for(int i=0; i<26; i++)
for(int j=0; j<26; j++)
bigrams[i][j] = 1.0;
double total = 26*26;
FILE * f;
char filename[100];
strcpy(filename, opt_language);
strcat(filename, "_bigrams.txt");
f = fopen(filename, "r");
if (!f)
{
fprintf(stderr, "Fatal error: Unable to open the language statistics file %s\n",
filename);
exit(1);
}
while(1)
{
char a;
char b;
int count;
int ret = fscanf(f, "%c%c %d\n", & a, & b, & count);
if (ret > 0)
{
if ((a >= 'A') && (a <= 'Z') && (b >= 'A') && (b <= 'Z'))
{
bigrams[char2num(a)][char2num(b)] = count + 1;
total += count;
}
}
else
break;
}
for(int i=0; i<26; i++)
for(int j=0; j<26; j++)
bigrams[i][j] = log10(bigrams[i][j]);
fclose(f);
}
void trigrams_read()
{
for(int i=0; i<26; i++)
for(int j=0; j<26; j++)
for(int k=0; k<26; k++)
trigrams[i][j][k] = 1.0;
double total = 26*26*26;
FILE * f;
char filename[100];
strcpy(filename, opt_language);
strcat(filename, "_trigrams.txt");
f = fopen(filename, "r");
if (!f)
{
fprintf(stderr, "Fatal error: Unable to open the language statistics file %s\n",
filename);
exit(1);
}
while(1)
{
char a;
char b;
char c;
int count;
int ret = fscanf(f, "%c%c%c %d\n", & a, & b, & c, & count);
if (ret < 1)
break;
if (ret > 0)
{
if ((a >= 'A') && (a <= 'Z') &&
(b >= 'A') && (b <= 'Z') &&
(c >= 'A') && (c <= 'Z'))
{
trigrams[char2num(a)][char2num(b)][char2num(c)] = count + 1;
total += count;
}
}
}
fclose(f);
for(int i=0; i<26; i++)
for(int j=0; j<26; j++)
for(int k=0; k<26; k++)
trigrams[i][j][k] = log10(trigrams[i][j][k]);
}
void quadgrams_read()
{
for(int i=0; i<26; i++)
for(int j=0; j<26; j++)
for(int k=0; k<26; k++)
for(int l=0; l<26; l++)
quadgrams[i][j][k][l] = 1;
unsigned int total = 26*26*26*26;
FILE * f;
char filename[100];
strcpy(filename, opt_language);
strcat(filename, "_quadgrams.txt");
f = fopen(filename, "r");
if (!f)
{
fprintf(stderr, "Fatal error: Unable to open the language statistics file %s\n",
filename);
exit(1);
}
while(1)
{
char a;
char b;
char c;
char d;
int count;
int ret = fscanf(f, "%c%c%c%c %d\n", & a, & b, & c, & d, & count);
if (ret < 1)
break;
if (ret > 0)
{
if ((a >= 'A') && (a <= 'Z') &&
(b >= 'A') && (b <= 'Z') &&
(c >= 'A') && (c <= 'Z') &&
(d >= 'A') && (d <= 'Z'))
{
quadgrams[char2num(a)][char2num(b)][char2num(c)][char2num(d)] = count + 1;
total += count;
}
}
}
fclose(f);
for(int i=0; i<26; i++)
for(int j=0; j<26; j++)
for(int k=0; k<26; k++)
for(int l=0; l<26; l++)
quadgrams[i][j][k][l] = log10(quadgrams[i][j][k][l]);
}
double quadgram_score(char * text, int len)
{
double score = 0.0;
for (int i=0; i<len-3; i++)
score += quadgrams
[char2num(text[i])]
[char2num(text[i+1])]
[char2num(text[i+2])]
[char2num(text[i+3])];
return score;
}
double trigram_score(char * text, int len)
{
double score = 0.0;
for (int i=0; i<len-2; i++)
score += trigrams[char2num(text[i])][char2num(text[i+1])][char2num(text[i+2])];
return score;
}
double bigram_score(char * text, int len)
{
double score = 0.0;
for (int i=0; i<len-1; i++)
score += bigrams[char2num(text[i])][char2num(text[i+1])];
return score;
}
double monogram_score(char * text, int len)
{
double score = 0.0;
for (int i=0; i<len; i++)
score += monograms[char2num(text[i])];
return score;
}
double ic_score(char * text, int len)
{
double freq[26];
for(int j=0; j<26; j++)
freq[j] = 0;
for(int i=0; i<len; i++)
freq[char2num(text[i])] += 1.0;
double score = 0.0;
for(int j=1; j<26; j++)
score += freq[j-1] * freq[j];
return score;
}
void init()
{
for (int i=0; i < rotor_count; i++)
for (int j=0; j < asize; j++)
{
rotor_fwd[i][j] = char2num(rotor_string[i][j]);
rotor_rev[i][j] = index(rotor_string[i],num2char(j)) - rotor_string[i];
notch[i][j] = index(notch_string[i], num2char(j)) != NULL;
}
for (int i=0; i < reflector_count; i++)
for (int j=0; j < asize; j++)
reflector[i][j] = char2num(reflector_string[i][j]);
}
void init_steckerbrett(const char * steckerbrett_string)
{
for (int j=0; j < asize; j++)
steckerbrett[j] = j;
int plug_count = strlen(steckerbrett_string) / 2;
for (int i=0; i < plug_count; i++)
{
int a = char2num(steckerbrett_string[2*i+0]);
int b = char2num(steckerbrett_string[2*i+1]);
steckerbrett[a] = b;
steckerbrett[b] = a;
}
}
void init_steckerbrett_direct(const char * steckerbrett_string)
{
for (int j=0; j < asize; j++)
steckerbrett[j] = char2num(steckerbrett_string[j]);
}
void init_walzen(int u, int a, int b, int c)
{
if (opt_norenigma)
{
ukw = 3+u;
walzenlage[0] = 8+a;
walzenlage[1] = 8+b;
walzenlage[2] = 8+c;
}
else
{
ukw = u;
walzenlage[0] = a;
walzenlage[1] = b;
walzenlage[2] = c;
}
}
void init_ring_grund(int a, int b, int c, int x, int y, int z)
{
ringstellung[0] = a;
ringstellung[1] = b;
ringstellung[2] = c;
grundstellung[0] = x;
grundstellung[1] = y;
grundstellung[2] = z;
}
char rotor_l(int x, int rotor_no)
{
int y = grundstellung[rotor_no] - ringstellung[rotor_no];
x = (x + asize + y) % asize;
x = rotor_fwd[walzenlage[rotor_no]][x];
x = (x + asize - y) % asize;
return x;
}
char rotor_r(int x, int rotor_no)
{
int y = grundstellung[rotor_no] - ringstellung[rotor_no];
x = (x + asize + y) % asize;
x = rotor_rev[walzenlage[rotor_no]][x];
x = (x + asize - y) % asize;
return x;
}
inline int mod26(int x)
{
return (x+26)%26;
}
inline void step_rotors()
{
if (notch[walzenlage[wheels-2]][grundstellung[wheels-2]])
{
grundstellung[wheels-3] = mod26(1+grundstellung[wheels-3]);
grundstellung[wheels-2] = mod26(1+grundstellung[wheels-2]);
}
else if (notch[walzenlage[wheels-1]][grundstellung[wheels-1]])
{
grundstellung[wheels-2] = mod26(1+grundstellung[wheels-2]);
}
grundstellung[wheels-1] = mod26(1+grundstellung[wheels-1]);
}
inline int subst_rotors(int x)
{
for (int r = wheels - 1; r >= 0; r--)
x = rotor_l(x, r);
x = reflector[ukw][x];
for(int r = 0; r < wheels; r++)
x = rotor_r(x, r);
return x;
}
inline int substitute(int x)
{
return steckerbrett[subst_rotors(steckerbrett[x])];
}
inline int step(int x)
{
step_rotors();
return substitute(x);
}
inline int step_precomputed(int x)
{
step_rotors();
return steckerbrett[subst_array
[mod26(grundstellung[0]-ringstellung[0])]
[mod26(grundstellung[1]-ringstellung[1])]
[mod26(grundstellung[2]-ringstellung[2])]
[steckerbrett[x]]];
}
void precompute()
{
int r1 = 0;
int r2 = 0;
int r3 = 0;
for (int g1 = 0; g1 < asize; g1++)
for (int g2 = 0; g2 < asize; g2++)
for (int g3 = 0; g3 < asize; g3++)
{
init_ring_grund(r1, r2, r3, g1, g2, g3);
for (int x = 0; x < asize; x++)
subst_array[g1][g2][g3][x] = subst_rotors(x);
}
}
void setup_mapping(int textlength)
{
if (textlength > maxlen)
fatal("Ciphertext too long");
/* set up mapping trough the rotors for each character in the ciphertext */
for (int i=0; i<textlength; i++)
{
step_rotors();
for (int j=0; j<26; j++)
mapping[i][j] = subst_array
[mod26(grundstellung[0]-ringstellung[0])]
[mod26(grundstellung[1]-ringstellung[1])]
[mod26(grundstellung[2]-ringstellung[2])]
[j];
}
}
inline void map(int len,
unsigned char * source,
unsigned char * map,
unsigned char * dest)
{
for (int i = 0; i < len; i++)
dest[i] = map[26*i + source[i]];
}
inline int step_mapped(int i, int x)
{
return steckerbrett[mapping[i][steckerbrett[x]]];
}
inline void decode(int textlength, char * ciphertext, char * plaintext)
{
for (int i = 0; i < textlength; i++)
plaintext[i] = num2char(step_mapped(i, num_ciphertext[i]));
//plaintext[i] = num2char(step_precomputed(char2num(ciphertext[i])));
//plaintext[i] = num2char(step(char2num(ciphertext[i])));
plaintext[textlength] = 0;
}
inline void map16_step(unsigned char * source,
unsigned char * map,
unsigned char * dest)
{
for (int i = 0; i < 16; i++)
dest[i] = map[26*i+source[i]];
}
inline void map16_direct(unsigned char * source,
unsigned char * map,
unsigned char * dest)
{
for (int i = 0; i < 16; i++)
dest[i] = map[source[i]];
}
void showit(const char * msg, unsigned char * p)
{
#if 0
fprintf(stderr, "%s:", msg);
for(int i=0; i<16; i++)
fprintf(stderr, " %2d", p[i]);
fprintf(stderr, "\n");
#endif
}
inline void decode_num()
{
#if 0
for (int i = 0; i < textlength; i++)
num_plaintext[i] = step_mapped(i, num_ciphertext[i]);
#else
#if 0
showit("cipher", num_ciphertext);
for (int i = 0; i < textlength; i++)
num_plaintext[i] = steckerbrett[mapping[i][steckerbrett[num_ciphertext[i]]]];
showit("plain ", num_plaintext);
fprintf(stderr, "\n");
#else
for (int i = 0; i < textlength; i += 16)
{
unsigned char temp1[16];
unsigned char temp2[16];
showit("cipher", num_ciphertext+i);
map16_direct(num_ciphertext+i, steckerbrett, temp1);
showit("steck ", temp1);
map16_step(temp1, ((unsigned char *)(&mapping[i])), temp2);
showit("mapped", temp2);
map16_direct(temp2, steckerbrett, num_plaintext+i);
showit("plain ", num_plaintext+i);
// fprintf(stderr, "\n");
}
#endif
#endif
}
double quadgram_score_decode(int textlength)
{
/* This decode and scoring function uses 99% of the computation time
when hill-climbing. */
decode_num();
/*
load triplet scores
load 16 bytes at adr
load 16 bytes at adr+1
load 16 bytes at adr+2
unpack low and high of each of these
shift 0, 5 or 10 bits left
add/or together
gather from triplet score table
*/
double score = 0.0;
for (int i=0; i<textlength-3; i++)
score += quadgrams[num_plaintext[i]][num_plaintext[i+1]]
[num_plaintext[i+2]][num_plaintext[i+3]];
return score;
}
double trigram_score_decode(int textlength)
{
decode_num();
double score = 0.0;
for (int i=0; i<textlength-2; i++)
score += trigrams[num_plaintext[i]][num_plaintext[i+1]][num_plaintext[i+2]];
return score;
}
double bigram_score_decode(int textlength)
{
decode_num();
double score = 0.0;
for (int i=0; i<textlength-1; i++)
score += bigrams[num_plaintext[i]][num_plaintext[i+1]];
return score;
}
double monogram_score_decode(int textlength)
{
decode_num();
double score = 0.0;
for (int i = 0; i < textlength; i++)
score += monograms[num_plaintext[i]];
return score;
}
double ic_score_decode(int textlength)
{
int freq[26];
for(int j=0; j<26; j++)
freq[j] = 0;
for (int i = 0; i < textlength; i++)
freq[step_mapped(i, num_ciphertext[i])]++;
double score = 0.0;
for(int j=1; j<26; j++)
score += freq[j-1] * freq[j];
return score;
}
void showsteckerbrett()
{
#if 0
for (int j=0; j<26; j++)
putchar(num2char(steckerbrett[j]));
#else
fprintf(stderr, "S:");
for (int j=0; j<26; j++)
if (steckerbrett[j] > j)
fprintf(stderr, " %c%c", num2char(j), num2char(steckerbrett[j]));
#endif
}
void showconfig()
{
fprintf(stderr,
"W: %c%d%d%d R: %c%c%c G: %c%c%c ",
num2char(ukw + (opt_norenigma ? 10 : 0)),
walzenlage[0] + (opt_norenigma ? -7 : 1),
walzenlage[1] + (opt_norenigma ? -7 : 1),
walzenlage[2] + (opt_norenigma ? -7 : 1),
num2char(ringstellung[0]),
num2char(ringstellung[1]),
num2char(ringstellung[2]),
num2char(grundstellung[0]),
num2char(grundstellung[1]),
num2char(grundstellung[2]));
showsteckerbrett();
fprintf(stderr, "\n");
}
struct subst_score_s
{
int a;
int b;
double score;
} subst_scores[26*26];
int subst_score_comp(const void * x, const void * y)
{
struct subst_score_s * i = (struct subst_score_s *) x;
struct subst_score_s * j = (struct subst_score_s *) y;
if (i->score < j->score)
return +1;
else if (i->score > j->score)
return -1;
else
return 0;
}
void all_subst_score(int textlength)
{
init_steckerbrett("");
#if 0
double score;
//score = ic_score_decode(textlength);
//score = mgram_score_decode(textlength);
//score = bigram_score_decode(textlength);
//score = trigram_score_decode(textlength);
//score = quadgram_score_decode(textlength);
printf("Base score: %.4f\n", score);
#endif
// srandomdev();
for (int a=0; a<26; a++)
for (int b=0; b<26; b++)
{
double score = -1e30;
if (a<b)
{
/* insert one plug */
steckerbrett[a] = b;
steckerbrett[b] = a;
score = random() % 10000;
//score = ic_score_decode(textlength);
//score = mgram_score_decode(textlength);
//score = bigram_score_decode(textlength);
//score = trigram_score_decode(textlength);
//score = quadgram_score_decode(textlength);
steckerbrett[a] = a;
steckerbrett[b] = b;
}
subst_scores[26*a+b].a = a;
subst_scores[26*a+b].b = b;
subst_scores[26*a+b].score = score;
}
/* sort */
qsort(subst_scores, 26*26, sizeof(subst_score_s), subst_score_comp);
#if 0
/* print */
for (int a=0; a<26*26; a++)
if (subst_scores[a].score > -1e30)
printf("%c%c: %8.4f\n",
num2char(subst_scores[a].a),
num2char(subst_scores[a].b),
subst_scores[a].score);
#endif
}
double score_iter(int iter, int textlength)
{
double score = 0;
switch(opt_scoring)
{
case 0:
score = ic_score_decode(textlength);
break;
case 1:
score = monogram_score_decode(textlength);
break;
case 2:
score = bigram_score_decode(textlength);
break;
case 3:
score = trigram_score_decode(textlength);
break;
case 4:
score = quadgram_score_decode(textlength);
break;
default:
fatal("Illegal scoring type");
}
return score;
}
int count[26];
int order[26];
int compare(const void * x, const void * y)
{
int a = count[*(int*)(x)];
int b = count[*(int*)(y)];
if (a<b)
return +1;
else if (a>b)
return -1;
else
return 0;
}
void ciphertext_letterdist(int textlength, char * ciphertext)
{
for(int j=0; j<26; j++)
{
count[j]=0;
order[j] = j;
}
for (int i=0; i<textlength; i++)
count[char2num(ciphertext[i])]++;
qsort(order, 26, sizeof(int), compare);
#if 0
fprintf(stderr, "Ciphertext letter order: ");
for(int j=0; j<26; j++)
fprintf(stderr, "%c", num2char(order[j]));
fprintf(stderr, "\n");
#endif
}
double hillclimb(int textlength,
char * ciphertext,
char * plaintext)
{
/* Try to find the optimal steckerbrett for the given other settings */
int best_steckerbrett[26];
memcpy(best_steckerbrett, steckerbrett, 26*sizeof(int));
/* calc and sort best initial plug */
// all_subst_score(textlength);
double best_score = -1e29;
double last_best = -1e30;
int iter = 1;
while (best_score > last_best)
{
best_score = score_iter(iter, textlength);
last_best = best_score;
double switch_score = best_score;
int switch_a = 0;
int switch_b = 0;
//#define SHOWHILLCLIMB
#ifdef SHOWHILLCLIMB
fprintf(stderr, " ");
for(int b=1; b<26; b++)
fprintf(stderr, " %c", num2char(b));
fprintf(stderr, "\n");
#endif
for(int a=0; a<26; a++)
{
#ifdef SHOWHILLCLIMB
fprintf(stderr, "%c:", num2char(a));
for(int b=1; b<a+1; b++)
fprintf(stderr, " ");
#endif
for(int b=a+1; b<26; b++)
{
/* switch plugs */
int x = steckerbrett[a];
int y = steckerbrett[b];
int xx = steckerbrett[x];
int yy = steckerbrett[y];
steckerbrett[x] = x;
steckerbrett[y] = y;
steckerbrett[a] = b;
steckerbrett[b] = a;
double score = score_iter(iter, textlength);
#ifdef SHOWHILLCLIMB
fprintf(stderr, "%4.0f", (score - best_score)/10.0);
#endif
if (score > switch_score)
{
switch_score = score;
switch_a = a;
switch_b = b;
}
/* restore plugs */
steckerbrett[a] = x;
steckerbrett[b] = y;
steckerbrett[x] = xx;
steckerbrett[y] = yy;
}
#ifdef SHOWHILLCLIMB
printf("\n");
#endif
}
if (switch_score - best_score > 0)
{
/* good move */
int a = switch_a;
int b = switch_b;
/* switch plugs */
int x = steckerbrett[a];
int y = steckerbrett[b];
steckerbrett[x] = x;
steckerbrett[y] = y;
steckerbrett[a] = b;
steckerbrett[b] = a;
#ifdef SHOWHILLCLIMB
fprintf(stderr,
"%2d %c%c Imp: %10.4f Score: %10.4f ",
iter,
num2char(a), num2char(b),
switch_score - best_score,
switch_score);
showsteckerbrett();
fprintf(stderr, "\n");
#endif
best_score = switch_score;
}
iter++;
}
decode(textlength, ciphertext, plaintext);
#ifdef SHOWHILLCLIMB
printf("Plaintext: %s\n", plaintext);
#endif